1. Field of Invention
The present invention relates to the field of design and construction of bicycle and like cycle seat clamping assemblies. More specifically, the present invention relates to assemblies that attach the rails or wires that form the lower portion of the seat to the seat post.
2. Discussion of Prior Art
In general, cycle seat clamping assemblies are used to attach the seat to the seat post.
This invention is primarily designed for lightweight applications. Weight is a very important design consideration in many types of bicycle and like cycle disciplines.
The prior art often allows adjustability in seat angle and horizontal position. In some prior art it is desirable to make adjustments with as few fasteners as possible. Other designs use more fasteners but are lighter weight or are easier to adjust. Some prior art states that it is better to adjust the seat angle and horizontal position simultaneously, while others claim independent adjustment is better. It is sometimes desirable to provide calibration scale to indicate the seat angle.
Another common feature in the prior art is to have rearward offset of the seat clamping assembly in the horizontal direction from the centerline of the post. This is done to put the rider's weight in a more preferred position while allowing the seat clamping assembly to clamp the seat in a more central position. Some bicycles work better with a horizontal offset and others are designed to work better without this offset. There is no true standard for horizontal offset.
The horizontal offset described above creates a need for support off the centerline of the seat post. This often leads to cantilevered support structures off the back of the seat post. These cantilevered support structures are often bulky and heavy due to the necessity to design for cantilever bending loads. Some examples of these cantilevered designs are U.S. Pat. Nos. 2,920,911 (1960) to Campagnolo, 4,275,922 (1981) to Juy, 4,568,121 (1986) to Kashima, 4,995,753 (1991) to Shook, 5,226,624 (1993) to Kingsberry, 5,547,155 (1996) to Herting, and 6,164,864 (2000) to Beach, Mizek, and Paes.
Some designs use threaded set screws or threaded rods as adjustments to the seat angle. These adjustments are sometimes hard to reach and difficult to adjust. The threaded rods or set screws also provide little structural support in any direction other than along the axis of the threaded shaft. This single direction of structural support necessitates additional weight, strength and stiffness in the other parts of the assembly. Some examples of assemblies with set screw or threaded rod seat angle adjustments are U.S. Pat. Nos. 4,995,753 (1991) to Shook, 5,226,624 (1993) to Kingsberry, 5,571,273 (1996) to Saarinen, and 6,174,027 (2001) to Lemmens.
U.S. Pat. No. 6,174,027 to Lemmens uses a seat support pivotably attached to one end of a seat post with a threaded rod and knob as an angular control adjustment between the seat support and the seat post. This example of prior art is not ideal for lightweight applications. The threaded rod adjustment only serves to define the seat angle by separating the seat support and seat post. The threaded rod provides no support in any other direction due to the necessity of the rod to rotate for adjustment. The threaded rod is continuously free to rotate about at least one end. Additionally, the threaded joints that the rod threads into do not provide significant support to resist side and bending loads since they must be kept loose enough to allow free movement of the threads. Furthermore, to make the threaded rod and knob adjustment easily available while the bicycle is being ridden it is located a considerable distance from the seat rails, making the seat support structure carry significant bending loads. This lack of structural support from the angular control adjustment and remote adjustment location with respect to the seat rails creates stress and load conditions that lead to a heavy and bulky assembly.